The suppository is a solid preparation at normal temperature, and when applied to rectum, urethra, vagina or the like, is softened or melted at the body temperature, or dissolved in local mucus to make the drug absorbed into the body through the mucous membrane.
In the suppository such as a drug for treating hemorrhoids, the oily or fatty base for the suppository acts as the lubricant upon evacuation and prevent becoming more serious condition.
Many suppositories being commercially available contain oily or fatty bases such as hard fat, cacao butter and the like and their melting point is adjusted to not higher than the body temperature in order to be softened or melted at around body temperature.
For the above reasons, as to the condition for storing the suppositories, it is required to keep the suppositories in cool storage at usually not higher than 15.degree. C. or at most 30.degree. C., or to preserve them in the upside position of the suppository down, therefore there are many limitations in storage compared with other formulations.
It is difficult to maintain good conditions for the suppository in the case where the suppository stands at high temperature for a long time, for example, in the summer or in the car during transportation. Therefore, after the suppository has been handed to the patient, it is particularly difficult to keep it in the good condition.
On the other hand, the suppository comprising macrogol and the like has a higher melting point so as to be dissolved in the local mucus and to exhibit the effect of the drug. Therefore, it hardly causes the problems described above in the suppository comprising an oily or fatty base, however, the patient may suffer from congestion, erythema or the like on mucous membrane caused by the physical stimulation of the suppository brought about by the absorption of mucus at the local area.
The suppository containing a higher alcohol, surfactant, absorption controlling agent and the like sometimes causes poor absorption or the sustained release of the drug. Further, it may have a side effect such as strong stimulation of the local mucous membrane.
These suppositories having a high melting point may not spread by the reasons, for example, that suppository administered in the rectum is not adequately melted or softened and may not play a role of the lubricant upon evacuation which is a characteristic of the suppository. Under the circumstances, one of the objects of the present invention is to provide a suppository which does not exhibit the quality deterioration such as the deformation and crack and shows the same drug release, internal absorbability, effect and safety as those of the conventional suppositories at the applied region.